package juc;

import java.util.HashMap;
import java.util.Hashtable;
import java.util.concurrent.ConcurrentHashMap;

/**
 * Created with IDEA
 * author:ju bai
 * Date:2021/5/30
 * Time:10:52
 * hashMap
 **/
public class Demo4 {
    public static void main(String[] args) {


        //非线程安全的
        HashMap hashMap = new HashMap();

        ConcurrentHashMap<String,String> map = new ConcurrentHashMap<>();

        Hashtable<String,String> hashtable = new Hashtable<>();

    }
}
